1. Field of the Invention
The present invention relates to a multi-spark ignition system for an internal combustion engine, in which an air-fuel mixture introduced into a combustion chamber is ignited via a spark plug. The ignition system may be operated both in single-spark operation and in multi-spark operation.
2. Description of Related Art
Ignition devices are already known in which an ignition coil is charged on the primary side and energy is introduced into a combustion chamber of a cylinder on the secondary side by short-circuiting the ignition coil. The duration of this ignition process is restricted to approx. one millisecond, and the flame development of the mixture depends on an ignitable mixture being present in the region of the electrodes at this point in time. However, in modern jet-directed internal combustion engines featuring gasoline direct injection the instant when the mixture at the electrodes is ignitable cannot always be restricted to the narrow time period of an ignition spark in a conventional single-spark ignition, due to the charge movement and reasons related to the combustion chamber.
To extend the ignition period, a multi-spark operation is provided, at least under certain operating conditions; during an ignition phase, the primary side of the ignition coil is charged and discharged multiple times, so that a quasi continuous electric arc is produced at the spark plug, which exists over a longer period of time than in a single-spark operation.